The suspension assembly of a vibration generating device fixed inside an axle of running gear of a vehicle, specifically an automotive vehicle is described.
It applies more particularly, but not exclusively, to a rear drive axle of a hybrid automotive vehicle supporting a drive unit including an electric traction machine.
The term axle is generally used to define a transverse connection piece joining the wheels of a vehicle. This transverse connection piece is also called a crossmember. The axle is equipped with various pieces connecting to the ground usually present in a running gear of an automobile vehicle. Specifically the axle supports suspension arms connecting the wheels to the vehicle. The axle is joined to the vehicle chassis in a known way by means of attachments such as pivot type joints.
The axle is arranged to support, the connection parts to the ground, noted above, and a motor device mounted suspended inside the axle which is a generator of vibrations.
The motor device may be an internal combustion engine or an electric traction machine, and generally any vibration generating device, vibrations that should be filtered to prevent their propagation toward the cabin. These vibrations are generated specifically by the acyclic movements well known in the internal combustion engines, but that exist also in the electric machines developing significant power and, specifically in the electric machines used for traction of the vehicles. These vibrations, combined with those generated by the wheels' suspensions, are transmitted to the chassis of the vehicle and are sources of discomfort for the occupants of the vehicle.
Document FR 2 837 754 discloses a suspension architecture of a drive unit in an automotive vehicle chassis.
FR 2 837 754 will be referenced usefully to understand the problems of the suspensions of the motors and to familiarize oneself with the vocabulary that will be used in this description.
The two main types of suspension motor architecture are: suspensions called “pendulée” (swinging), used specifically by the auto maker PSA Peugeot Citroën; and suspensions called “posée” (composed) used specifically by the auto maker Toyota.
The choice of the suspension architecture type is dictated specifically by the type of motor device used: the suspension modes generated by the device motor and the stresses due to the weight of the motor device and its torque, as well as the desired installation of the motor device in the vehicle.
In the case of an electric machine, the so-called swinging architecture, is difficult to install and not of interest because the electric machine does not generate any stress called “pilon” (tamper) as is the case with a standard internal combustion engine.
The architecture called “posée” (compose) implies the design of parts that must withstand the stresses, due to the weight of the machine, as well as its torque, following the one and same direction along the Z axis, while considering the three-dimensional reference coordinates X Y Z illustrated in FIG. 1.
This reference system will be used in the entire description that follows to describe in space, the axle and the element carriers of the electric machine with the convention:                the X axis, oriented from the front to the rear of the vehicle 1;        the Y axis, oriented from the left side of the vehicle 1 to the right of the vehicle 1 (while looking at the vehicle head on, facing the front of the vehicle 1); and        the axis Z, oriented from bottom to top.        
This architecture implies that the six suspension modes, enumerated in the document FR 2 837 754, are coupled together and are hardly “configurable”.
Neither of these two architectures is satisfactory to respond to the dual constraint linked to the installation of an electric machine within a running gear which is itself suspended.